igor999
Forum Senior
Topics: 56
Posts: 83
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Where does polymerization of molecules into collagen fibrils occur in?
A) Ribosomes
B) Lysosomes
C) Extracellular Space
D) Rough ER
E) Smooth ER
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| igor999
Forum Senior
Topics: 56
Posts: 83
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It would be nice of someone to state the course of collagen from beginning to start and which compartments it goes through.
For example, hydroxylation of collagen occurs in Rough ER.
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| Jackofknives
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In cytosol:
Alfa-chain systehsis starts here, where the amino-terminal signal sequences bind signal recognition particles and enters RER through translocons. Then signal peptides are cleaved.
In RER lumen:
Hydroxylation of proline and lysine resideues occurs cotranslationally, before assembly of a triple helix. Cofactors are Fe2+ and ascorbate.
Proline hydroxylation is important for stabilization, lysine hydroxylation provides sites for specific glycosylation in the ER.
So glycosylation, just like most proteins, takes place in the ER.
Here polypeptide chains has completed
In cytoplasm:
Triple helix assembly, this include formation of disulfide bonds, winding etc.
In golgi:
Some sulfation, phosphorylation, not important.
In extracellular space:
Ofc conversion of procollagen to collagen.
Amino and carboxyl terminal propeptides are cleaved by proteases.
Triple helices assembil into fibrils, crossing linking etc.
There is some lysyl oxidase involved, but that’s not important.
So answer is C
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| igor999
Forum Senior
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i just wanted to say thanks for such a nice thorough review of collagen synthesis. i wish other students can reap and learn from what you wrote. thanks again.
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| Jackofknives
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my pleasure
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| medocuk
IM-RES
Topics: 26
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Hey Jack of knives thanks for simplifying this. I am going to copy paste this onto my journal with slight modifications. I hope that is OK with you.
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| Jackofknives
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sure go ahead
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There are many things in this world that can’t be changed no matter how hard you try. That’s why you must not hesitate when the time comes where you have to give it all you’ve got.
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| Ig F
Forum Elite
Topics: 3
Posts: 440
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everything ahead after the relaease of procollagen helix from the endoplasmic reticulum occurz in the extracellular spaces
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